KR101004981B1 - Gallium oxide-zinc oxide sputtering target, method for forming transparent conductive film, and transparent conductive film - Google Patents

Abstract

assignment

A high density gallium oxide-zinc oxide-based sintered compact sputtering target for forming a transparent conductive film, comprising 20 to 2000 mass ppm of zirconium oxide. The gallium oxide (Ga ₂ O ₃ ) -zinc oxide (ZnO) -based sputtering target (GZO-based target) for forming a transparent conductive film improves conductivity and bulk density of the target by adding a small amount of a specific element, ie, improves the composition of the component, thereby sintering The present invention provides a method for forming a transparent conductive film using the same target, while providing a target capable of raising the density and suppressing nodule formation to prevent abnormal discharge and particle generation.

Sputtering Target, Transparent Conductive Film

Description

GALLIUM OXIDE-ZINC OXIDE SPUTTERING TARGET, METHOD FOR FORMING TRANSPARENT CONDUCTIVE FILM, AND TRANSPARENT CONDUCTIVE FILM}

The present invention provides a gallium oxide (Ga ₂ O ₃ ) -zinc oxide (ZnO) -based sputtering target (GZO-based target) capable of obtaining a transparent conductive film capable of maintaining a good visible light transmittance and conductivity, and a transparent conductive film using the target. It relates to a method and a transparent conductive film formed thereby.

Conventionally, an ITO (doped indium oxide with a tin) film is transparent and excellent in conductivity as a transparent conductive film, and is widely used for transparent electrodes (films) or solar cells of display devices such as liquid crystal displays and electro luminescence displays. It is used for a purpose. However, this ITO has a problem that it is inferior in terms of manufacturing cost because indium which is a main component is expensive.

In this regard, proposals have been made to use a GZO film as a substitute for ITO. Since GZO is a zinc oxide based film mainly composed of gallium oxide (Ga ₂ O ₃ ) -zinc oxide (ZnO), it has an advantage of low cost. It is known that the GZO film is a phenomenon in which conductivity increases due to oxygen deficiency of ZnO as a main component, and there is a possibility that the utilization thereof may be increased when the film characteristics of conductivity and light transmittance approximate ITO.

As a method of forming this GZO film, it is mainly performed according to the sputtering method, and in particular, it is formed using direct current (DC) sputtering, high frequency (RF) sputtering, or magnetron sputtering in terms of operability and film stability.

Formation of the film by the sputtering method physically collides positive ions such as Ar ions with a target provided on the cathode, and releases the material constituting the target with the collision energy, thereby causing the target material to face the substrate on the anode side facing the film. It is carried out by laminating a film of almost the same composition as.

The coating method according to the sputtering method is characterized by forming a thin film of an angstrom unit to a thick film of several tens of micrometers at a stable film forming speed by adjusting the processing time, the supply power, and the like.

Several proposals have been made regarding a sintered compact sputtering target for forming such a GZO film or a transparent conductive film formed thereby.

For example, Patent Literature 1 discloses a zinc oxide-based sintered compact in which a part of the target material is free of abnormal discharge and that a stable thin film can be formed, and a Ga ₂ O ₃ -ZnO target sintered compact is used in the target material of the partial. There is proposed a target containing zinc oxide obtained by selectively adding 1 to 5% by weight of titanium oxide, germanium oxide, aluminum oxide, magnesium oxide, indium oxide, and tin oxide.

Patent Document 2 is a GZO sintered compact sputtering target capable of forming a stable thin film without occurrence of abnormal discharge. The powder particle diameter of zinc oxide and gallium oxide is finely made to 1 µm or less, and the sintering temperature is set to 1300-1550 ° C. The technique of adjusting and improving density by sintering while introducing oxygen is proposed.

Patent Literature 3 discloses a GZO sintered sputtering target having a low occurrence of abnormal discharges over a long period of time, high transmittance and low resistance, and a third element selected from Ga of 3 to 7 atomic%, Al, B, In, Ge, Si, Sn, and Ti. ZnO system sintered compact in which 0.3-3 atomic% was added is proposed.

Patent Document 4 proposes a technique for sputtering in an atmosphere made of hydrogen gas and an inert gas in order to prevent zinc oxide from reacting with moisture and changing electrical and optical properties.

In general, a problem particularly in the case of forming a GZO film is that sputtering causes fine projections, called nodules, to occur in the erosion portion of the target surface, and also causes abnormal discharge or splash caused by the nodules, resulting in sputter chambers. Coarse particles (particles) are suspended in the particles and adhere to the formed film, which causes deterioration of quality. In addition, the abnormal discharge causes a problem that the plasma discharge state becomes unstable and that stable film formation cannot be performed.

Therefore, when the conductive film is formed on the substrate, it is necessary to periodically remove the nodules generated on the sputtering target, and this causes a problem of remarkably lowering the productivity. Thus, a target with little nodule generation and no abnormal discharge phenomenon occurs. It is required.

In particular, in recent years, since there is a tendency for display enlargement and a large area film formation is required, a target capable of stable film formation is particularly required.

In the above-mentioned patent document, the problem of abnormal discharge has been pointed out. As a countermeasure for abnormal discharge, as described above, in Patent Document 1, titanium oxide, germanium oxide, aluminum oxide, magnesium oxide, indium oxide, and tin oxide are selectively selected. It is proposed to add -5 wt%, and to add 3 to 3 atomic% of the third element selected from Al, B, In, Ge, Si, Sn, Ti in Patent Document 3.

These are all intended to prevent abnormal discharge by raising the density of a sintered compact and reducing the space | gap in a sintered compact. However, even with such an additive, there is a problem that the sintered density does not sufficiently increase and the bulk (volume) resistance is high.

Moreover, although the manufacturing process of a target is improved, making a manufacturing process complicated becomes a cost factor, and when it is necessary to improve a density by improving a sintering method or apparatus, there is a problem that a facility needs to be enlarged. It is not an industrially efficient method.

Overall, adding a trace element, i.e. changing the composition of the GZO sintered body, improves the density of the target, prevents nodule formation, and suppresses abnormal discharge phenomenon and particle generation. Since the change in the composition of the component may deteriorate the bulk resistance value of the target, and the sintered density may not necessarily be improved, there is a problem that sufficient measures cannot be taken in the examples shown in the patent document. have.

It is an optical disk protective film and the sputtering target for protective film formation (refer patent document 5) as a technique with a component composition approximating. However, the purpose of this technique is to provide an optical disk protective film, which contains 1 or 2 or more of ZnO, In ₂ O ₃ or SnO ₂ as a main component, and further contains Al ₂ O ₃ or Ga ₂ O ₃ or ZrO ₂ . If to be suitable as a protective film for the optical disc Ga ₂ 0 ₃ is 0.1~20wt% is in the optimum range, which also added to Zr0 ₂ has been described as 0.01~5wt%.

In this case, of course, the objective is to obtain an optical disk protective film, and not to have a function as a conductive film. Although this is inevitable because it uses an optical disk protective film, it can be said that the technique disclosed in this patent document 5 does not recognize that utility as a transparent conductive film and electroconductivity accompanying it are obtained.

Patent Document 1: Japanese Patent Application Laid-Open No. 10-306367

Patent Document 2: Japanese Patent Application Laid-Open No. 10-297964

Patent Document 3: Japanese Patent Application Laid-Open No. 11-256320

Patent Document 4: Japanese Unexamined Patent Publication No. 2002-363732

Patent Document 5: Japanese Unexamined Patent Publication No. 2000-195101

Disclosure of Invention

Problems to be Solved by the Invention

In view of the problems of the prior art, the gallium oxide (Ga ₂ O ₃ ) -zinc oxide (ZnO) -based sputtering target (GZO-based target) of the present invention improves conductivity and density by adding a small amount of a specific element, that is, a component composition It improves, raises a sintering density, suppresses nodule formation, obtains the target which can prevent abnormal discharge and particle generation, and provides the method of forming a transparent conductive film using this target, and the transparent conductive film formed accordingly It is.

Means to solve the problem

Above, the present invention

1) High density gallium oxide-zinc oxide-based sintered compact sputtering target for forming a transparent conductive film, which contains 20 to 2000 massppm of zirconium oxide

2) A gallium oxide-zinc oxide-based sintered sputtering target for forming a transparent conductive film according to the above 1), characterized in that it contains 0.1 to 10 mass% of gallium oxide.

3) A high density gallium oxide-zinc oxide-based sintered sputtering target for forming a transparent conductive film according to the above 1) or 2), wherein the sintered density is 5.55 g / cm 3 or more.

4) The high density gallium oxide-zinc oxide sintered compact sputtering target for transparent conductive film formation in any one of said 1) -3) whose bulk resistance value of a target is 3.0 m (ohm) or less.

5) forming a thin film made of gallium oxide-zinc oxide containing 20-2000 massppm of zirconium oxide on a substrate by sputtering using a gallium oxide-zinc oxide-based target containing 20-2000 massppm of zirconium oxide; Formation method of transparent conductive film

6) A method for forming a transparent conductive film according to the above 5), wherein the transparent conductive film contains 0.1 to 10 mass% of gallium oxide.

7) A transparent conductive film excellent in conductivity made of a gallium oxide-zinc oxide system, characterized by containing 20 to 2000 massppm of zirconium oxide formed on a substrate by sputtering.

8) A transparent conductive film having excellent conductivity as described in 5) above, characterized by containing 0.1 to 10 mass% of gallium oxide in the transparent conductive film.

9) The transparent conductive film which is excellent in the electroconductivity of the said 7) or 8) description is provided that the specific resistance of a transparent conductive film is 5 m (ohm) * cm or less.

Effects of the Invention

The gallium oxide (Ga ₂ O ₃ ) -zinc oxide (ZnO) -based sputtering target (GZO-based target) contains 20 to 2000 massppm of zirconium oxide (ZrO ₂ ), thereby significantly improving the density of the target, The bulk resistance can be suppressed constantly. With this, it is possible to suppress the formation of nodules generated during sputtering film formation, to reduce abnormal discharge over a long period of time, and to obtain a target capable of preventing the generation of particles.

In addition, it is possible to form a transparent conductive film having a high transmittance and a low resistance value by using the target, and a remarkable effect of providing a transparent conductive film formed thereby.

1 is a graph showing the relationship between the zirconium oxide (ZrO ₂₎ content and sintered density and bulk resistance value in the case of sintering at 1400 ℃ according to the embodiment and the comparative example GZO series target of the present application.

2 is a graph showing the relationship between the amount of zirconium oxide (ZrO ₂ ) addition, the sintered density and the bulk resistance value when sintered at 1450 ° C. in the GZO system targets of Examples and Comparative Examples of the present application.

3 is a graph showing the relationship between the amount of zirconium oxide (ZrO ₂ ) addition, the sintered density and the bulk resistance value when sintered at 1500 ° C. in the GZO system targets of Examples and Comparative Examples of the present application.

To practice the invention  Best form for

Generally, the electroconductivity of a transparent conductive film is represented by area resistance ((ohm) / square), and the area resistance of about 5 (ohm) / square is normally required. In the case of applying to the liquid crystal display screen as described above, high area resistance and low area resistance are required. Area resistance is expressed by dividing the specific resistance by the thickness of the transparent conductive film.

The area conductivity of the transparent conductive film is expressed by the product of the conductivity (the inverse of the specific resistance) and the film thickness, and the conductivity σ (Ω ^-1 ㆍ cm ^-1 ) is included in the carrier (hole or electron) included in the film. It is expressed by the product of the charge e (clone), the carrier mobility μ (cm 2 / V · sec) and the carrier concentration n (cm ⁻³ ) (σ (Ω ⁻¹ · cm ⁻¹ ) = e · μ · n).

Therefore, in order to improve the electrical conductivity of the transparent conductive film and to lower the resistivity (also referred to as resistivity) and the area resistance, one or both of the carrier mobility μ (cm 2 / Vsec) and the carrier concentration n (cm ^-3 ) are increased. Just do it.

The gallium oxide-zinc oxide type sintered compact sputtering target of this invention is excellent as a target for transparent conductive film formation which has such a film characteristic. As gallium oxide amount, it is preferable to contain in the range of 0.1-10 mass%. More preferably, it is 2-7 mass%.

As a factor which determines the film characteristics at the time of sputtering, although the density of a target is mentioned as mentioned above, the higher the density of a target, the less nodule formation, the abnormal discharge generation and particle generation are suppressed over a long period, and it is stable. Sputtering characteristics and a favorable film can be obtained.

On the other hand, since the bulk resistance value of the target is directly reflected in the resistivity of the transparent conductive film, the increase in the bulk resistance value should be suppressed as much as possible.

In the gallium oxide-zinc oxide-based sintered compact sputtering target of the present invention, it was found that zirconium oxide (ZrO ₂ ) 20 to 2000 massppm is very effective as a dopant capable of achieving high density. Moreover, this zirconium oxide has a characteristic that it is solid-solvated to GZO and can maintain a low bulk resistance value as mentioned later. The addition of this zirconium oxide is the most important point of this invention.

If the zirconium oxide is less than 20 massppm, the density of the target cannot be achieved, so it is set to 20 massppm or more. On the other hand, when zirconium oxide exceeds 2000 massppm, the bulk resistance increases. There is also a problem that excessive addition of zirconium oxide causes cracking of the target. Therefore, it is necessary to be 2000 massppm or less.

Moreover, the sintered density of the high density gallium oxide-zinc oxide type sintered compact sputtering target of this invention can achieve 5.55 g / cm <3> or more, Furthermore, 5.6 g / cm <3> or more.

In addition, the bulk resistance value of the high density gallium oxide-zinc oxide-based sintered compact sputtering target of the present invention can achieve 3.0 mΩ or less. In the conventional gallium oxide-zinc oxide-based sintered sputtering target, the density and sintering density of 5.6 g / cm 3 or more and the bulk resistance can not simultaneously achieve 3.0 mΩ or less.

Since the bulk resistance value of a target is directly reflected by the resistivity of a transparent conductive film, the addition amount of gallium oxide needs to be content which reduces a bulk resistance value. For this purpose, the gallium oxide amount is set to 0.1 to 10 mass%. Thereby, the transparent conductive film excellent in the electroconductivity and light transmittance of a gallium oxide zinc oxide system can be obtained.

The method for producing the GZO target of the present invention is not particularly limited, but a predetermined amount (0.1-10 mass%) of gallium oxide (Ga ₂ O ₃ ) powder, a small amount of zirconium oxide (ZrO ₂ ) 20-2000 massppm powder, and a residual zinc oxide Prepare (ZnO) powder.

In general, in order to improve the density of the target, the finer the powder is, the better the finer it is, but in the present invention, the zirconium oxide (zirconia) is used as the dopant to be added to GZO. It can be used as a media. That is, there is an advantage that it can be pulverized using a container of zirconia beads or zirconia lining, and the pulverizing media itself does not become a source of contamination (contamination source).

Thereby, there exists a big advantage that the level of grinding | pulverization can be improved and a sputtering target of higher purity and a high density can be obtained compared with the former.

For example, it can mix and grind | pulverize with an AtoWriter, and can obtain the mixed powder slurry which is 0.8 micrometer in median diameter. This slurry is granulated and spherical granulated powder is obtained. Moreover, this granulated powder can be press-molded and CIP (isotropic cold press) can further be performed. And this molded object is sintered for about 1 to 5 hours at the temperature of about 1000-1600 degreeC in oxygen atmosphere, and a sintered compact is obtained.

In addition, the sintering conditions can be arbitrarily changed, and the manufacturing method of powder can also be changed other than the above, and is not specifically limited. By the above, a sintered density of 5.55 g / cm <3> or more, Furthermore, 5.6 g / cm <3> or more can be achieved.

This sintered compact is ground and cut, and it is processed into the target for sputtering of a predetermined shape, and the gallium oxide- zinc oxide type sintered compact sputtering target containing 0.1-10 mass% of zirconium oxide and gallium oxide of predetermined amount is obtained.

Next, using these sintered compact sputtering targets, a transparent electrode film is formed using DC sputtering, RF sputtering, magnetron sputtering, or the like on a glass substrate. Although the glass generally uses light-transmissive substrates, it should be understood that the glass is not particularly limited.

Since a gallium oxide-zinc oxide type sintered compact target has electroconductivity, it can form into a film easily by DC sputter | spatter. Therefore, it is preferable to form a film using a simple, reliable and most stable DC sputtering device. Representative examples of DC sputtering conditions are shown below.

This sputtering condition can also be changed arbitrarily.

Sputter gas: Ar 90 to 100%, 0 to 10% O ₂

Sputter gas pressure: 0.1 to 5 Pa

Power amount: 0.2 ~ 6W / ㎠

Deposition speed: about 100 to 300 s / min

Substrate temperature: room temperature to 300 ° C

Next, the Example of this invention is described. In addition, this embodiment is an example to the last, It is not limited to this example. That is, all the aspects or modifications except an Example are included within the scope of the technical idea of this invention.

(Examples 1 to 6)

20 massppm (Example 1), 50massppm (Example 2), 200massppm (Example 3), 500massppm (Example 4), 1000massppm (Example 5) of ZrO ₂ minutes having an average particle diameter of 1 μm or less after crushing by zirconia media, respectively ), And weighed at 2000massppm (Example 6), and weighed respectively to be Ga ₂ O ₃ powder: 5mass% and residual zinc oxide (ZnO), and then these were used as crushed media of zirconia (ZrO ₂ ) balls or beads. The mixture was ground and pulverized with an AtoWriter to obtain a mixed powder slurry having a median diameter of 0.8 µm.

This slurry was granulated to obtain spherical granulated powder. Moreover, this granulated powder was press-molded and CIP (isotropic cold press) was further performed. And this molded object was sintered for 5 hours at the temperature of 1400 degreeC, 1450 degreeC, and 1500 degreeC in air | atmosphere, respectively, and the sintered compact was obtained. This sintered compact was ground and cut | disconnected, and was processed into the target for sputtering of a predetermined shape.

And the density and bulk resistance of the sintered compact target obtained by this were measured. The results are shown in Table 1, Table 2, and Table 3. In addition, this was graphically shown in FIG. 1, FIG. 2, FIG. The zirconium oxide (ZrO ₂ ) contained in the target measures the amount of zirconium according to ICP (inductively coupled plasma method), and the ZrO ₂ equivalent amount is calculated | required with respect to the target whole quantity. The amount of ZrO ₂ contained in the target became the same amount as the amount added before sintering. Target density was measured according to the Archimedes method. The bulk resistance value was randomly determined at five points over almost the entire surface of the mirror-polished target, measured using a four-needle method at a depth of 2 mm from the surface of the target cut surface, and the average value was employed.

Table 1 and Fig. 1 shows the case of sintering at 1400 ° C, Table 2 and Fig. 2 shows the case of sintering at 1450 ° C, and Table 3 and Fig. 3 shows the case of sintering at 1500 ° C. As shown in Table 1-Table 3, and FIGS. 1-3, as a sintering temperature becomes high over 1400 degreeC-1500 degreeC, there exists a tendency for density to become high and a bulk resistance value fall.

However, when the sintering temperature becomes high, evaporation (volatilization) of the material occurs, and there is a fear that a change in composition occurs because the amount of evaporation differs depending on the components constituting the target. Particularly, at a temperature of 1400 ° C or higher, part of the zinc oxide evaporates from the target surface, and it becomes remarkable as the temperature becomes high. Although it is necessary to remove the layer which the composition variation generate | occur | produced by cutting, when the layer which shifted the surface composition by the sintering at high temperature increases, the problem that the cutting amount will increase and a yield will fall will arise.

As well as energy loss due to high temperature sintering, this composition fluctuation needs to be suppressed as much as possible. In this sense, it can be said that it is preferable to be 1400 degrees C or less as possible.

Therefore, although sintering at a lower temperature is preferable, in this case, since lowering density and high bulk resistance occur, it is preferable to adjust this balance and select appropriately according to the conditions of the required density and bulk resistance of the target. can do.

Table 1 and FIG. 1 show the case of sintering at 1400 ° C., and the high density gallium oxide-zinc oxide-based sintered sputtering target of the present example to which 20-2000 massppm of zirconium oxide was added was gallium oxide- free of ZrO ₂ (Comparative Example 1 described later). Compared with the zinc oxide-based sintered sputtering target, the density and bulk resistance are remarkably improved. That is, it has a density of 5.34-55.4 g / cm <3>, and a bulk resistance value is 2.83-3.18 m (ohm) * cm, and it turns out that a preferable high density and low bulk resistance value are obtained. Moreover, the crack of the target did not generate | occur | produce.

Table 2 and FIG. 2 show the case of sintering at 1450 ° C., and the high density gallium oxide-zinc oxide-based sintered sputtering target of the present example to which 20-2000 massppm of zirconium oxide was added was gallium oxide- free of ZrO ₂ (Comparative Example 1 described later). Compared with the zinc oxide-based sintered sputtering target, the density and bulk resistance are remarkably improved. That is, it has a density of 5.52-55.5 g / cm <3>, and a bulk resistance value is 2.23-2.68 m (ohm) * cm, It turns out that a more preferable high density and low bulk resistance value are obtained. Moreover, the crack of the target did not generate | occur | produce.

Table 3 and FIG. 3 show the case of sintering at 1500 ° C., and the high density gallium oxide-zinc oxide-based sintered sputtering target of the present embodiment to which 20-2000 massppm of zirconium oxide was added was added without gallium oxide (ZrO ₂ ) (Comparative Example 1 described later). Compared with the zinc oxide-based sintered sputtering target, the density and bulk resistance are remarkably improved. In other words, it has a density of 5.62 to 5.44 g / cm 3, and the bulk resistance value is 1.77 to 2.65 mΩ · cm, and it can be seen that preferable high density and low bulk resistance values are obtained. Moreover, the crack of the target did not generate | occur | produce.

Next, DC sputtering was performed on the glass substrate using this sputtering target on the following conditions, and the amount of nodule generation (coating rate) and abnormal discharge were measured and observed. The amount of nodule generation (coating rate) measured the abnormal discharge 10 hours after sputtering by the surface observation 1 hour after the sputtering start.

Sputter Gas: Ar (100%)

Sputter gas pressure: 0.6Pa

Power amount: 1500W

Film formation speed: 120Å / min

As a result, in the case of 1400 degreeC sintering shown in Table 1, the nodule coverage of Examples 1-6 was 0.418 to 0.895%, and was 1039 hours after sputtering, and the frequency | count of abnormal discharge is 239-462 times, And the number of occurrences of abnormal discharges was small.

Table 2 shows the nodule coverages of Examples 1 to 6 at 1450 ° C sintering, which is lower than that of 1400 ° C sintering, resulting in 0.189% to 0.406%, and sputtering after 10 hours of sputtering. Likewise, the number of times was lower than that of 1400 ° C sintering, resulting in 135 to 259 times, and the number of occurrences of abnormal discharges was small.

Moreover, although the nodule coverage of Examples 1-6 was shown in Table 3 at 1500 degreeC sintering, it is still lower than the case of 1450 degreeC sintering, and becomes 0.042 to 0.126%, and abnormal discharge in sputtering after 10 hours sputtering The number of times was also lower than that of the 1450 ° C sintering, which was 68 to 107 times, and the occurrence number of abnormal discharges was remarkably small.

In Table 3, the specific resistance of the sputtered film of Examples 1-6 in the case of 1500 degreeC sintering is shown. The specific resistance of the sputtered film was in the range of 0.56 to 0.62 mΩ · cm, and both of them satisfied the condition of the specific resistance of the transparent conductive film defined by the present invention dsp: 5 mΩ · cm or less. In this case, the specific resistance of the sputtered film in the case of using a target sintered at 1500 ° C is shown. The same applies to the case of sintering at 1400 ° C and 1450 ° C.

The film properties of the resistivity (? · Cm) of the film formation and the transmittance% at 550 nm were examined, and exhibited good transmittance of visible light and high conductivity almost without comparable with a standard ITO film. Of gallium oxide Ga ₂ O ₃ 5mass% addition amount in the above example - been described with respect to zinc oxide sintered sputtering target, a range of the gallium oxide% 0.1~10mass, it is possible to obtain the same result.

(Example 7)

ZrO ₂ powder having an average particle diameter of 1 µm or less after pulverization by zirconia media was weighed at 500 massppm, and then weighed so as to be Ga ₂ O ₃ powder: 5 mass% and residual zinc oxide (ZnO), followed by zirconia (ZrO ₂ ) balls. Alternatively, beads were used as the grinding media and mixed and finely pulverized with an Atolighter to obtain a mixed powder slurry having a median diameter of 0.8 µm.

As in Examples 1 to 6, this slurry was granulated to obtain spherical granulated powder. Moreover, this granulated powder was press-molded and CIP (isotropic cold press) was further performed. And this molded object was sintered at the temperature of 1500 degreeC in nitrogen atmosphere for 5 hours, and the sintered compact was obtained.

This sintered compact was ground and cut | disconnected, and was processed into the target for sputtering of a predetermined shape. And Table 3 shows the result of having investigated this target characteristic and the characteristic in the case of sputtering similarly to Examples 1-6.

As a result, the sintered compact had a density of 5.64 g / cm 3, the bulk resistance value was satisfactory at 1.48 mΩcm, and no cracking of the target occurred. Although the nodule coverage increased slightly to 0.330%, the number of abnormal discharges was reduced by 42 times, and the sputter film specific resistance was 0.22 mΩcm, indicating a very good value. Thus, it turned out that sintering in inert atmosphere shows more favorable characteristic. In the present Example, although the characteristic of the target and thin film was sintered at 1500 degreeC with favorable characteristics, the same tendency as the Examples 1-6 was seen also in sintering of 1400 degreeC and 1450 degreeC.

(Comparative Examples 1 and 2)

In the absence of ZrO ₂ minutes (Comparative Example 1) and ZrO ₂ minutes having an average particle diameter of 1 μm or less after pulverization by zirconia media were weighed at 5000 massppm (Comparative Example 2), respectively, the Ga ₂ O ₃ powder was further added. It was weighed so as to have residual zinc oxide (ZnO) at 5 mass%.

Next, zirconia (ZrO ₂ ) balls (beads) were used as the grinding media, and these were mixed and pulverized with an atomizer to obtain a mixed powder slurry having a median diameter of 0.84 µm. This slurry was granulated to obtain spherical granulated powder.

Moreover, this granulated powder was press-molded and CIP (isotropic cold press) was further performed. And this molded object was sintered for 10 hours at the temperature of 1400 degreeC, 1450 degreeC, and 1500 degreeC in air | atmosphere, respectively, and the sintered compact was obtained. These sintered bodies were ground and cut | disconnected and processed into the target for sputtering of a predetermined shape.

And the density and bulk resistance of the sintered compact target obtained by this were measured. This result is shown to Table 1, Table 2, and Table 3 similarly. In addition, this was graphically shown in FIG. 1, FIG. 2, FIG. In addition, the zirconium oxide (ZrO ₂ ) target density and bulk resistance contained in the target were measured in the same manner as in Example.

As shown in Table 1 and FIG. 1, in Comparative Example 1 which is a gallium oxide-zinc oxide-based sintered compact sputtering target in the absence of addition, when sintered at 1400 ° C., the sintered density was 5.23 g / cm 3 and the bulk resistance value was 2.1 × 10. ⁵ mΩ · cm (2.1E + 05mΩ · cm), when sintered at 1450 ° C., the sintered density is 5.39 g / cm 3 and the bulk resistance value is 3.42 mΩ · cm, and when sintered at 1500 ° C., the sintered density Was significantly lowered to 5.48 g / cm 3, and the bulk resistance value was increased to 3.30 mΩ · cm.

As shown in these, under the same sintering conditions, it becomes lower density and higher bulk resistance than any example, and it turns out that it is unsuitable as a gallium oxide- zinc oxide type sintered compact sputtering target.

On the other hand, in Comparative Example 2, the gallium oxide containing 5000massppm the ZrO ₂ represents a - if sintered in the zinc oxide based sintered sputtering target, if the sintering at 1400 ℃ and 1450 ℃ has been density is lowered, there is a tendency that the bulk resistance value increased. And when it sintered at 1500 degreeC, density is low as 5.58 g / cm <3>, bulk resistance value becomes 2.50 m (ohm) * cm, and it turns out that it is unpreferable as a target. The targets obtained at the sintering temperature were all cracked.

Next, the transparent electrode film was formed in the glass substrate by DC sputter | spatter on the conditions similar to an Example using these sintered compact targets.

In the same manner as in Example, the nodule generation amount (coating rate) was measured by the surface observation 1 hour after the start of sputtering, and the abnormal discharge measured the abnormal discharge 5 hours after sputtering. The results are shown in Table 1.

When the gallium oxide-zinc oxide type sintered compact sputtering target which is the zirconium oxide no addition of the comparative example 1 was sintered at 1400 degreeC, bulk resistance was too high and DC sputtering was impossible. Moreover, although the target sintered at 1450 degreeC and 1500 degreeC could DC sputter | spatter, the coverage of the nodule and the frequency of abnormal discharge were many, and were bad.

On the other hand, in a gallium oxide-zinc oxide-based sintered sputtering target containing 5000 massppm of ZrO ₂ shown in Comparative Example 2, when sintered at 1400 ° C., sintered at 1450 ° C., and sintered at 1500 ° C., compared with the present example. As a result, the coverage of the nodule and the number of abnormal discharges increased, resulting in a defect.

Moreover, although the specific resistance of the film | membrane in the case of using sputter | spatter using the target of Comparative Example 1 and Comparative Example 2 sintered at 1500 degreeC in Table 3, it tended to become higher than the specific resistance of an Example in all. The tendency of this comparative example 1 and the comparative example 2 showed the same tendency of the specific resistance of the film | membrane when sputtering using the target sintered at 1400 degreeC and 1450 degreeC.

In the above, the case where 5000 massppm of zirconium oxide was added was demonstrated, but the same result was obtained even if 2500 massppm and 3000 massppm were added.

(Comparative Examples 3, 4, 5)

Next, ZrO case of _two minutes with no additives (Comparative Example 3), ZrO ₂ minutes if the 2000massppm added (Comparative Example 4), ZrO ₂ minutes if the 5000massppm added with respect to (Comparative Example 5), CIP (isostatic cold press) treatment The result of having investigated the target characteristic at the time of sintering at 1500 degreeC, and the characteristic at the time of sputtering using this target is shown in Table 3 similarly, without implementing. In addition, the manufacturing method of a target, the formation method of a sputter | spatter film, and the evaluation method of a target and a film | membrane were implemented on the conditions similar to the comparative example 1.

As shown in Table 3, the sintered density of the target was all lower than in Example, and in Comparative Example 5, the occurrence of cracking was also observed. The bulk resistance value was 3.23 to 3.70 mΩcm, and both were higher than in the examples. In addition, the nodule coverage at the time of sputtering was unusually high at 0.846 to 1.086%, and the number of abnormal discharges was also significantly increased as compared with the 426 to 628 circuit examples. The specific resistance of the sputtered film was also very high, from 1.06 to 1.26 mΩcm. In all, the fall of the characteristic was remarkable compared with the Example.

The tendency of this comparative example 1 and the comparative example 2 showed the same tendency of the specific resistance of the film | membrane when sputtering using the target sintered at 1400 degreeC and 1450 degreeC.

As indicated above, by adding an appropriate amount of zirconium oxide, the sputtering characteristics, in particular, the coverage of the nodule are suppressed, and the generation of particles caused by abnormal discharge or splash caused by the nodule is suppressed, and the quality of the conductive film is suppressed. It turns out that a fall can be suppressed effectively.

However, if the amount of zirconium oxide added is less than 20 massppm, the effect is not effective. If the amount of zirconium oxide is exceeded 2000 massppm, the bulk resistance is increased, and the improvement of sintered density is not observed. Is preferably in the range of 20 massppm to 2000 massppm.

In addition, zirconium oxide can be used as a medium for fine grinding. In other words, it can be pulverized using a container of zirconia beads or zirconia lining, and there is an advantage that the pulverizing medium itself does not become a source of contamination (contamination source). As such, the addition of an appropriate amount (small amount) of zirconium oxide is very effective for improving sputtering characteristics.

The gallium oxide (Ga ₂ O ₃ ) -zinc oxide (ZnO) -based sputtering target (GZO-based target) contains 20 to 2000 massppm of zirconium oxide (ZrO ₂ ), thereby significantly improving the density of the target and providing a bulk resistance value. It can be suppressed constantly. In addition, with this, nodule formation occurring during sputtering film formation can be suppressed, and abnormal discharge can be reduced over a long period of time, and particle generation can be prevented. Thereby, the transparent electrode film which can maintain favorable transmittance and electroconductivity of visible light can be obtained.

Therefore, it is useful for a wide range of uses, such as a transparent electrode (film) of a display device, such as a liquid crystal display and an electroluminescent display, or a solar cell.

Claims (9)

A high-density gallium oxide-zinc oxide-based sintered compact sputtering target for forming a transparent conductive film, containing 20 to 2000 massppm of zirconium oxide, and having a bulk resistance of 3.0 mΩ · cm or less. The method of claim 1, A gallium oxide-zinc oxide-based sintered compact sputtering target for forming a transparent conductive film, comprising 0.1 to 10 mass% of gallium oxide. The method according to claim 1 or 2, A high density gallium oxide-zinc oxide-based sintered compact sputtering target for forming a transparent conductive film, wherein the sintered density is 5.55 g / cm 3 or more. delete A method for forming a transparent conductive film, comprising using a sputtering target according to claim 1 or 2, wherein a thin film made of gallium oxide-zinc oxide containing 20 to 2000 massppm of zirconium oxide is formed on a substrate by a sputtering method. The method of claim 5, 0.1-10 mass% of gallium oxide is contained in a transparent conductive film, The formation method of the transparent conductive film characterized by the above-mentioned. 20 to 2000 massppm of zirconium oxide formed on a substrate by sputtering, and the resistivity of the transparent conductive film is 5.0 m? · Cm or less. The method of claim 7, wherein 0.1-10 mass% of gallium oxide is contained in a transparent conductive film, The transparent conductive film excellent in electroconductivity characterized by the above-mentioned. A method for forming a transparent conductive film, comprising forming a thin film made of gallium oxide-zinc oxide containing 20 to 2000 massppm of zirconium oxide on a substrate by the sputtering method using the sputtering target according to claim 3.

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